方程2x²+3x-1=0 ,b²-4ac的值是 a.-1 b.1 c.5 d.17
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![方程2x²+3x-1=0 ,b²-4ac的值是 a.-1 b.1 c.5 d.17](/uploads/image/z/1628764-52-4.jpg?t=%E6%96%B9%E7%A8%8B2x%26%23178%3B%2B3x-1%3D0+%2Cb%26%23178%3B-4ac%E7%9A%84%E5%80%BC%E6%98%AF+a.-1+b.1+c.5+d.17)
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方程2x²+3x-1=0 ,b²-4ac的值是 a.-1 b.1 c.5 d.17
方程2x²+3x-1=0 ,b²-4ac的值是 a.-1 b.1 c.5 d.17
方程2x²+3x-1=0 ,b²-4ac的值是 a.-1 b.1 c.5 d.17
b²-4ac=9-4*2*(-1)=17
选D
d.17
3²-4x2x(-1)=9+8=17
a=2,b=3,c=-1.b²-4ac=17
d.17